Identification and Reproduction

Identification:

• Yellow hawkweed is a creeping perennial that grows from long fibrous roots. 
• Stems are upright, unbranched and hairy. When broken stems exude a milky juice. Stems can grow up to one metre tall. 
• Basal leaves range from elliptical to ovate and narrow near the petiole. Both sides of the leaves are hairy. 

• Produces ray flowers that are yellow and clustered at the end of stems. 

• It blooms from May to July and seed set occurs by August. 

Reproduction: 

• This plant can reproduce through rhizomes, stolons and seeds. 
• Rhizomes can creep and sprout daughter plants. 
• It is a prolific seed producer; seeds have germination rate and can disperse at great distances. 

Habitat & Ecology

• It invades disturbed areas, meadows, forested sites, gravel pits, pastures and roadsides. 
• It prefers sunny areas but can be shade tolerant. 
• Yellow hawkweed prefers well-drained, coarse-textured soils that has a low organic content. 

Impacts

Social: 

• Reduce livestock forage availability. 
• Decrease crop yields and rangeland quality. 

Ecological: 

• It outcompetes native plants, reducing forage and biodiversity. 
• Can threaten species at risk. 
• Forms monocultures that can suppress native species. 
• Reduce wildlife forage. 

Management

Mechanical/Manual Contol: 

• Treatments should be applied prior to seed set. 
• For small infestations hand-pulling and digging can be effective. Be cautious of breaking roots and stolons as these will resprout. 
• Young rosettes can be dug up and removed. 
• Bag and dispose of plant parts in the garbage. 
• For larger infestations reoccuring mowing can help reduce seed production. 

Chemical Control: 

• Picloram, aminopyralid, 2,4-D are effective on yellow hawkweed. 
• Another consideration is to fertilize surrounding native vegetation in the spring. This will help facilitate growth to help outcompete with the invader. 
• Please carefully read and follow herbicide labels prior to application.

Resources

• Factsheet for Yellow Hawkweed: Invasive Species Council of BC
• Key to Identification of Invasive and Native Hawkweeds: BC Ministry of Forests

Header photo (Konstantin Ryabitsev).